360° video (or spherical video) is an important media format for many applications, including those providing immersive environments for virtual reality (VR) and augmented reality (AR). A viewer of a 360° video may view the video at arbitrary angles and possibly within a small field of view (FOV). Accordingly, to appear sharp, a 360° video may need a much higher resolution than a regular video. In such scenarios, a 360° video stream may require much higher bitrates than a conventional video stream. For example, while a typical 1080p video may have a bitrate of about 1 MBps (or 60 MB file size for 1 minute video), a 360° video of the same view resolution may include a bitrate of about 10 MBps or more (or 600 MB file size for 1 minute video). The view resolution may include the resolution of a video frame that a viewer may observe at a given point in time.
The bitrate of a 360° video may be higher than data transfer rates in existing consumer level wireless networks. As a result, 360° videos may be pre-downloaded and/or aggressively down-sampled for streaming, which may be undesirable, if not unacceptable, for some applications.
View-aware streaming methods, which stream portions of the 360° video based on a user's view, have been used for video telepresence applications, but only with significant computational cost in streaming server. View-aware streaming has also been applied to 360° video streaming, but with significant extra storage cost at the server.